Field of the Invention
The invention relates to a connection device between the ends of tubes and a box from which there emerges a plurality of cables.
The field of the invention is that of a wired network for telecommunications, power, lighting or signalling.
More particularly, a description shall be given of a wired telecommunications network that itself brings together several types of networks to which there correspond various morphologies of infrastructure. A distinction may be made between;
interconnection networks, which connect networks of distinct telecommunications operators. The connections between these networks use underground conduits that are operated jointly.
transmission networks belonging to one or more operators and comprising nodes called telecommunications exchanges. The transmissions are sometimes made by means of RF channels but, given the quantity, confidentiality and need to securitize the information to be transmitted, it is often preferred to use cable transmission, especially transmission by fiber-optic cables, Various types of cables are used for these transmissions: overhead cables that do not always provide a sufficient degree of security to an operator and therefore expose his infrastructure, undersea or sub-fluvial cables which are very costly to lay down and are used only in case of necessity and, finally, underground cables and cables in buildings.
the distribution network, also called a xe2x80x9clocal loopxe2x80x9d, which indicates the part of the network located between a telecommunications exchange and the customer. In a rural environment, low population density makes it possible to optimize investments by using overhead cables, or satellite, radio or RF wireless transmission means. Conversely, in an urban environment, the population density encourages the use of underground conduits. The dimensioning of these networks varies according to the operators but the topology remains identical: a set of chambers with underground or roadway access, generally connected by underground conduits. This topology offers protection to the cables, and facilitates their installation. It also makes it possible to subsequently reach the cables or carry out work on them, depending on the development of the network which may require the dismounting of the cables. In the case of the Applicant, France Telecom, this network generally consists of cable access chambers connected by ducts with a diameter of less than 80 mm, laid out in groups over that may vary from a few meters up to 300 m.
the private telecommunications networks that companies, local authorities and other entities set up in order to facilitate the exchange of internal information independently of the operator. This mode of exploitation makes it possible to share the resources at lower cost. In certain cases, the large number of the buildings in a company entails the making of connections external to the buildings. If these buildings are localized in the same site, then the morphology of the infrastructure may be similar to that of the distribution network described here above. If the sites are distant, then the company calls in a telecommunications operator in order to use his network. In this case, the information goes through a distribution network and then a transmission network.
Various morphologies of infrastructure may thus be considered, depending on the network considered and the approach adopted: the cables may or may not be laid in plain earth, they may or may not be buried in concrete or bitumen, laid in underground conduits or even undersea or sub-fluvial conduits, fixed to overhead supports resting on posts, walls, etc. The underground infrastructure is currently the most frequently used approach. The invention generally applies to any infrastructure and more particularly to an underground infrastructure.
Hereinafter, we shall recall a certain number of definitions which will make it possible to understand and locate the field of the invention more clearly.
In the present invention, the term less than  less than leads greater than  greater than shall be understood to mean both copper wires for telephone transmission and elements in which light can be propagated such as optical fibers. These optical fiber elements may be filamentary and assembled in elements in ribbon form often known as ribbon cables. The term less than  less than leads greater than  greater than may also designate filamentary elements or elements in the form of electrically conductive strips, made especially of metal wire, for example copper.
The term less than  less than cable greater than  greater than is understood to mean the unit constituted by one or more leads protected by a sheath or jacket. In the literature, a less than  less than cable greater than  greater than is sometimes called a lead.
2. Description of the Prior Art
There are several cable structures in existence. Among the optical cables, we may refer to the cable comprising a group of 4 to 10 modules with 6 to 24 optical fibers, the diameter of this type of cable reaching up to 18 mm, and the microcable possibly containing up to 24 optical fibers gathered, as the case may be, in modules whose diameter varies between 1,5 to 6,5 mm, which corresponds to a reduction in diameter by a factor of 3.
As indicated in FIG. 1b), in certain cases, the cables 9 are laid freely in the ducts 14. In other cases, they are sheltered by one or more tubes 2 having a rigidity greater than that of cables 9. The reduction in costs associated with the miniaturization of the diameters of the cables makes it possible to envisage the laying of a plurality of small tubes in the ducts. In the distribution networks, the diameter of these tubes varies from 5 to 18 mm and they are made out of materials like polyvinyl chloride (PVC), polyethylene (EP) and polypropylene (PP).
The term less than  less than cable access chamber greater than  greater than or less than  less than junction chamber greater than  greater than is understood to mean a space into which the cables or the tubes lead or from which they leave. These cable access chambers can be prefabricated or built on the spot. They are often placed laid beneath the sidewalk and are made of reinforced concrete. In these cable access chambers, the cables are often connected to boxes.
The term less than  less than box greater than  greater than is understood to mean an element that facilitates and protects the connection of the leads and the cables. There are mainly two types of boxes. The in-line box is characterized by an entry and exit of cables on opposite sides of the box. When all the cables enter and exit on the same side, it is called a splice box. These boxes are tightly sealed, shield the leads and the connections and facilitate subsequent work.
The rigidity of the tubes, which are made for example of PVC, favors laying a tube in plain earth, or burying it concrete, or placing it in ducts and ensures that the dimensional specifications of the tube will be maintained. In the concept of miniaturization of the diameters of the cables and tubes, the small-sized tubes are flexible enough to reach the box directly instead of cables: extra lengths of tubes may then be stowed and, if necessary, coiled in the cable access chamber pending subsequent work. However, the increase in the stiffness and number of these tubes and the management of the extra lengths causes the cable access chambers to be encumbered. This does not facilitate work. In other cases, the tubes are cut at the entrance to the cable access chamber or a little after it, thus releasing the cables, which are more flexible than the tubes. However, if the flexibility of the cables improves the ergonomic quality of subsequent operations, the cables, thus released from the tubes or tubes, travel unprotected up to the box and are thus vulnerable.
The present invention makes it possible to overcome these disadvantages by proposing a connection device to a box of cables coming from tubes, ensuring the transition between tubes and cables and the protection of the cables up to the box. It thus facilitates the removal of a box from the cable access chamber or the shifting of this box while making it possible to store large extra lengths of protected cables, without being handicapped by the rigidity of the tubes, and generally, making it very easy to carry out operations of verification and repair.
In the device for connection between the ends of tubes protecting one or more cables and a box, a flexible sheath makes it possible, at the output of the tubes, to connect the cables coming from the tubes to the tubes to the box, in protecting them and enabling the shifting of the box that is to be accessed.
The flexible sheath advantageously comprises a pipe with an extruded or helically folded envelope and could include a connecting piece at each of its ends to provide for assembly or disassembly.
According to another characteristic, the device comprises a collector of tubes to assemble the ends of the tubes. Moreover, the collector is capable of including means to ensure the tightly sealed passage of the cables. These means advantageously comprise an elastomer membrane.
According to another characteristic, the collector is connected to the sheath. The collector possibly comprises ducts to hold the tubes in position.
The ducts may be located on the periphery of the collector.
To facilitate the passage of the cables from the collector to the sheath, the device comprises a transition element located between the collector and the sheath.
An object of the invention is also a method of access to cables arriving at a box located in a cable access chamber, consisting in placing said cables in a flexible sheath of a length sufficient to be able to shift the box to be reached.